Smart terminals, for example, smart phones, tablets, and other devices equipped with touch sensitive user inputs, are nowadays, common consumer electronic devices. The consumer electronic devices, such as smart phones and other smart terminals, as compared to conventional cell phones, are typically equipped with a better display device, and further include a user-friendly input device, such as a touch sensitive, or simply a touch input device. For example, a capacitive touch screen is typically used as an input device in smart phones, along with other touch screen technologies.
Generally, in a touch input device, a user may interact with the touch input device using gestures made by fingers. In alternative examples, special user input devices, such as a stylus, may be used to interact with the touch input device. Typically, such user interactions, or gestures, involve identifying a location of the gesture, or the location of the user input device, such as a user's finger during the gesture, on the touch input device. Sensing a location the user input device may include the following steps. For example, in case of a user's finger interacting with an operational surface of a capacitive touch screen, when the finger touches the capacitive screen, a coupling capacitor may be formed between the finger and the operational surface due to the electric field of the human body. The operational surface may be connected to a high-frequency signal. This may cause a small current to be absorbed by the finger, where the current may be flowing from electrodes at four corners of the operational surface. The currents flowing through the four electrodes may be proportional to respective distances from the fingertip to the four corners. The touch screen, using controllers or processors, or other circuitry, for precisely calculating the four current proportions, may derive the location of the gesture.
However, in the touch input device described above, the location, or position information of the user's finger, or any other user input device is sensed when the user's finger touches the touch input device. If the user's finger does not come in contact with the touch input device, even though the user's finger may be in close proximity to the touch input device, the touch input device may not be able to sense the gesture the user is going to perform, such as a click operation on the touch input device.